Quark confinement mechanism and QCD phase transition

1. Conefinement by Density-dependent quark masses (CDDM)

2. Comparison with the bag mechanism3. EoS of quark matter in CDDM4. EoS of nuclear matter in Breuckner theory

4. Some preliminary results

GUCAS & IHEP, Chinese Academy of SciencesNational Natural Science Foundation Committee of China

G.X.Peng 彭光雄 gxpeng@gucas.ac.cn

Ref: PRC 77(2008)065807; 72(2005)015204; 62(2000)025801; 61(2000) 015201

More stable: nuclear or quark matter?

Quark confinement mechanism

MIT bag

CDDM

Drawback of bag model (I)

Sound velosity not zero for massless quarks

Drawback of bag model (II): EoS always concave

Confinement by density-dependent quark masses

CDDM

History

1. Fowler, Raha, Weiner suggested

Z. Phys. C 9 (1981) 271

2. Chakrabarty, Raha, Sinha extended it to include strange quarks

Phys. Lett. B 229 (1989) 112Phys. Rev. D 43 (1991) 627; 48 (1993) 1409

Europhys. Lett. 56 (2001) 361; Phys. Rev. C 67 (2003) 015202.

3. Zhang and Su et. al. extended it to include temperature

Main weakpoints of the previous treatment

PRD 51 (1995) 1989, PRD 52 (1995) 1276

1. The quark mass scaling is not derived2. The vacuum limits are incorrect3. There are thermodynamic problems

Confinement by density-dependent quark masses

Quark mass scaling

Quark mass scaling

Z=1/3, T=150—170 MeV

Thermodynamic consistency

Peng et al, PRC 77 (2008) 065807

Schematic comparison (I)

Schematic comparison (II)

EoS of quark matter at finite density and temperature

Transition from nuclear to quark matter (II)

nm qm

Gibbs Conditions 吉布斯条件

Conservations 守衡律

1. Electric charge

2. Baryon number

=0

Nuclear EOS in the Brueckner theory with three-body forces

The pressure

The energy density

Phase diagram at zero temperature

Structure of compact stars

道可道，非常道，名可名，非常名。无名，天地之始；有名，万物之母。故常无，欲以观其妙；常有，欲以观其徼。此两者，同出而异名，同谓之玄；玄之又玄，众妙之门。

Critical densities for given proton fractions

道可道，非常道，名可名，非常名。无名，天地之始；有名，万物之母。故常无，欲以观其妙；常有，欲以观其徼。此两者，同出而异名，同谓之玄；玄之又玄，众妙之门。

Isentropic evolution of QGP

道可道，非常道，名可名，非常名。无名，天地之始；有名，万物之母。故常无，欲以观其妙；常有，欲以观其徼。此两者，同出而异名，同谓之玄；玄之又玄，众妙之门。

Properties of strangelets

道可道，非常道，名可名，非常名。无名，天地之始；有名，万物之母。故常无，欲以观其妙；常有，欲以观其徼。此两者，同出而异名，同谓之玄；玄之又玄，众妙之门。

Summary

We have provided a new approach toconsider quark confinement. It is appliedto investigating the QCD Phase transition, the evolution of a QGO, the stractureof compact stars, and prperties ofstrangelets, etc.